G'Kar is trying to warn people on Babylon 5 – anyone that will listen – that the Centauri will not rein in their aggression now that they've conquered the Narn Homeworld. A fellow Narn steps in and begs him to come away; there is a matter to discuss among the Narns on the station. Unknown to them, Vir Cotto has been observing with a strange look on his face.

Meanwhile, Ambassador Delenn has been summoned to see Ambassador Kosh in an empty hallway. Kosh explains that he has summoned an inquisitor: to make sure she is acting for the right reasons. She is also warned this test will place her life in danger.

Delenn and Lennier explain the situation to Captain John Sheridan. The Vorlons believe that people who lead for the wrong reasons corrupt and ultimately destroy that which they lead. The inquisitor is coming to make sure she is leading the Rangers aboard Babylon 5 for all the right reasons.

G'Kar is meeting with a black market arms dealer, Mr. Chase, to try to provide arms for a resistance on his homeworld. However, with hostility on the rise, the price is steep. G'Kar reluctantly agrees but firmly warns the dealer to deliver or face a gruesome fate.

Commander Susan Ivanova steps into C&C just as Lt. David Corwin reports a ship exiting the local jumpgate. It's revealed to be a Vorlon ship, which piques her curiosity since the only Vorlon ship to regularly come and go from the station was Kosh's ship. Ivanova relays the news to Sheridan.

Sheridan goes into the docking bay and relieves the security officer on duty. As per Delenn's request, he is seeing to this new arrival personally and with all due expediency. The inquisitor emerges into view: a human, wearing clothes appropriate for late 19th-century England, and using a cane.

The man deflects Sheridan's questions as they walk down the corridors. Seeing people in their daily life in the Zócalo, the inquisitor notes that nothing has changed – there is stil "corruption, immorality, chaos." His unusual attitudes makes Sheridan more than a little concerned. Finally, after some prodding, he tells Sheridan a few salient facts about himself. The man introduces himself as Sebastian, and he did live in London in the late 19th century until the Vorlons took him in and showed him things that made him the way he is now. He has been brought out of stasis by the Vorlons so he can perform a test uniquely suited to him. He then demands to get to work.

Security Chief Michael Garibaldi confronts G'Kar, pointing out that he's getting word about his contact with the black market. Despite what's been going on, that kind of activity is against station policy and would contribute to increasing chaos and instability aboard the station. But since G'Kar is honest and even a bit frank about what he's doing, Garibaldi offers help in his own way; he gives G'Kar info on alternate supply lines to keep his activities away from the station.

Sheridan contacts Delenn, informing her that the inquisitor has arrived. He tells her to go to Grey 19, where he is waiting and where they will be alone. Once she is sealed within the section, Sebastian gets straight to work. He makes her don a pair of manacles. She must keep them on for the entire session or she will be judged unfit: implying the manacles will affect her in some way during the test. Only when she dons them does Sebastian step forward to begin the inquisition. His questions seem simple but he expects unusual answers. He is cold, unyielding, even mocking of Delenn's words. His words have common themes: disdain of self-importance, of higher callings. He also reminds her that she could even die here. Whether she lives or not depends on her actions here.

Cotto is being harassed by a Centauri seeking audience with Ambassador Londo Mollari. Deflecting him, he steps into a transport tube, not realizing that G'Kar is already inside. He is now in an extremely awkward situation as he feels he has to justify his presence before the Narn. However his people had acted in the previous nine months, Vir was personally against their actions but lacked the influence to change things. The only thing Vir can think of saying to G'Kar in that moment is apologize for his race. As the tube door opens and G'kar steps out, he draws a knife, but he then cuts his own hand and lets the drops of blood serve as a message. Since Vir's apology cannot reach the Narns who died, G'Kar cannot accept it.

Sebastian's inquisition of Delenn continues. His admonitions turn to the subjects of glory and destiny, and he continues to belittle Delenn. He pointedly challenges Delenn to "call out to the universe" and see if it will respond. It is at this point that he activates the manacles. Electrical energy makes her cry out in pain: confirming them to be a torture implement. After a brief session, he challenges that supposition, challenging her to wonder if she really does exist for a reason. Suppose the universe refuses to acknowledge her? Delenn then admits that she could be wrong. For showing that glimmer of humility, Sebastian stops the inquisition for ten minutes.

G'Kar gathers the Narns on the station to help organize a resistance. But the other Narn are reluctant to trust him with their sacrifices. They need some reassurance. Most of all, they need word from home: word had been cut off since the Centauri conquest. G'Kar is in a bind because he lacks that kind of resources, but they make it clear that if he can't bring messages from home, they can't trust him to reliably deliver weapons to their homeworld. So G'Kar forges an agreement: their trust in exchange for messages from home, and if he cannot deliver within 24 hours, he will step aside.

Back in Grey 19, Sebastian distills Delenn's problem to an overinflated ego: a sense of being more than she really is. But now, Delenn fires back. She calls out Sebastian as a bully: one who relishes in administering pain and suffering. She sees a man whose dreams have been shattered and has no other option left but to lash out in retaliation. In other words, she realizes Sebastian is one of those found "unfit". In response, Sebastian increases the intensity. The inquisition becomes even more severe.

G'Kar goes to Captain Sheridan with a request. Can he find a way to get some kind of message from the Narn homeworld? Sheridan points out that G'Kar is asking a lot, especially given the urgency of the request, but he promises to do what he can. After G'Kar leaves, Sheridan reveals this is an excellent job for the Rangers. They need to start getting involved, and this scouting mission will be just the thing to start forging them into a greater force. G'Kar wouldn't be making this request if his leadership wasn't in question. If they succeed, G'Kar would maintain his stabilizing influence over the Narns on the station.

Lennier walks into Grey 19 to find Delenn lying on the floor, barely conscious. Delenn begs Lennier to leave before Sebastian returns. But she explains the situation: "How can I pass the test if I do not understand the rules?" At her insistence, Lennier leaves as the tap of Sebastian's cane can be heard. Lennier immediately goes to Sheridan, begging him to defy Kosh and stop the inquisition...before Delenn is killed.

After a lengthy torture, Sebastian points out that Delenn has no control over her fate. At this point, Sebastian notes the arrival of Sheridan: "the final player in our little drama". Sheridan enters, his PPG drawn, demanding Delenn be released. When Sebastian asks him some questions, he deflects them with defiance. Suddenly, with a tap of his cane, a flame erups from the floor, and Sheridan is thrown back against the wall. Sebastian then reveals that it now Sheridan's turn to endure his inquisition.

Sheridan is secured to a lattice in the room, and Sebastian sadistically points out that just because he won't answer his questions doesn't mean he can't watch his continued session with Delenn. He then asks a very interesting question, "Are you willing to die friendless, alone, deserted by everyone?" Sheridan still refuses to answer, but Sebastian keeps pressing. Would he sacrifice his friends? His family? His gods? As he keeps asking questions, he tortures Sheridan until Delenn stands up and demands he stop. She is the one to be tested, not he. Sheridan tells Delenn to leave, but Sebastian responds that any move will mean Sheridan or she dies. But Delenn stands defiant. Would she trade her life for his, despite her supposed destiny? She responds that should she fall, another will take up her cause, for as long as it is needed to complete the task. Her cause is life itself. So Sebastian asks if she is willing to give her life to save Sheridan. Is she willing to die unloved, unseen, unknown, unsung, for the sake of this one man? She answers that his words and action will not change her mind. Sebastian raises his cane as if to strike the life out of Delenn; but a moment later, he vanishes. Sheridan is unbound. The two embrace reassuringly as the door to the room opens. Sebastian awaits them at the exit and says, "You can go. You've passed – both of you." He reveals that the test involved both of them. Each proved willing to fade into obscurity and die alone in the dark just for the sake of another. Neither sought glory nor fame: only what is right, and that is the right reason the Vorlons had wanted to see. For the first time, Sebastian seems relieved, as he believes his task is finished at long last while theirs is just beginning.

Later, in C&C, Sheridan ponders what had just happened. Ivanova walks up and reports that Sebastian's ship is about to leave. He then asks her to consult the station's history files about an address: the same one Sebastian told him when he first arrived on the station.

The Narns on Babylon 5 gather around a screen which is displaying recorded messages from Narns back on the homeworld. The collective message is reassuring for everyone; everyone is still fighting. The Narns on the station now regard G'Kar with respect and admiration. G'Kar kept his word, and now they will keep theirs. They will place their trust in him.

As Sebastian is about to depart, Sheridan confronts him. The address he was given earlier turned up a very interesting fact. Sebastian did indeed live in London in the late 19th century. In fact, he disappeared mysteriously on November 11, 1888. At the same time, a string of murders in London's East End abruptly came to an end. Sebastian does not deny it. He explains that he had seen corruption in the city and had been endeavoring to wipe it clean. On that day, the Vorlons came to him and revealed that he had been acting for the wrong reasons. For the last 400 years he had been serving the Vorlons in his unique capacity: namely weeding out the unfit. Now, given that he has finally found people worthy of their cause, maybe the Vorlons will finally end his pathetic existence: "Remembered not as a messenger, remembered not as a reformer, not as a prophet, not as a hero, not even as Sebastian...remembered only...as Jack."

"No greater love hath a man than he lay down his life for his brother. Not for millions, not for glory, not for fame--for one person, in the dark, where no one will ever know or see. I have been in service to the Vorlons for centuries, waiting for you: Diogenes and his lamp looking for an honest man willing to die for all the wrong reasons."

– Sebastian

“

"A message needed to be sent, etched in blood for all the world to see. A warning."

– Sebastian

“

"Good luck to you in your holy cause, Captain Sheridan. May your choices have better results than mine. Remembered not as a messenger, remembered not as a reformer...not as a prophet, not as a hero...not even as Sebastian. Remembered only...as Jack."

As Sheridan talks to Sebastian while seeing him off, he mentions the date (Nov. 11, 1888) Sebastian disappears, revealing it as the day after the last day of a series of gruesome murders. You can read his lips as he says "West Side" (even read it in the closed captioning as West Side) but it was over-dubbed as "East Side". Interestingly the Netflix copy of this episode keeps the original audio track that states "West End."

Though it never made it to print, "The Book Of War", the cancelled 12th issue of the Babylon 5 comic book series to have been published by DC Comics would have revealed that Marcus Cole was the Ranger that was sent to the Narn Homeworld to obtain the "family messages" for G'Kar.[1]

This episode contains the first definitive statement regarding Vorlon interference in Earth history.